import ClockRange from '../../Core/ClockRange.js'
import defined from '../../Core/defined.js'
import destroyObject from '../../Core/destroyObject.js'
import DeveloperError from '../../Core/DeveloperError.js'
import JulianDate from '../../Core/JulianDate.js'
import getElement from '../getElement.js'
import TimelineHighlightRange from './TimelineHighlightRange.js'
import TimelineTrack from './TimelineTrack.js'

let timelineWheelDelta = 1e12

const timelineMouseMode = {
  none: 0,
  scrub: 1,
  slide: 2,
  zoom: 3,
  touchOnly: 4
}
const timelineTouchMode = {
  none: 0,
  scrub: 1,
  slideZoom: 2,
  singleTap: 3,
  ignore: 4
}

const timelineTicScales = [
  0.001,
  0.002,
  0.005,
  0.01,
  0.02,
  0.05,
  0.1,
  0.25,
  0.5,
  1.0,
  2.0,
  5.0,
  10.0,
  15.0,
  30.0,
  60.0, // 1min
  120.0, // 2min
  300.0, // 5min
  600.0, // 10min
  900.0, // 15min
  1800.0, // 30min
  3600.0, // 1hr
  7200.0, // 2hr
  14400.0, // 4hr
  21600.0, // 6hr
  43200.0, // 12hr
  86400.0, // 24hr
  172800.0, // 2days
  345600.0, // 4days
  604800.0, // 7days
  1296000.0, // 15days
  2592000.0, // 30days
  5184000.0, // 60days
  7776000.0, // 90days
  15552000.0, // 180days
  31536000.0, // 365days
  63072000.0, // 2years
  126144000.0, // 4years
  157680000.0, // 5years
  315360000.0, // 10years
  630720000.0, // 20years
  1261440000.0, // 40years
  1576800000.0, // 50years
  3153600000.0, // 100years
  6307200000.0, // 200years
  12614400000.0, // 400years
  15768000000.0, // 500years
  31536000000.0 // 1000years
]

const timelineMonthNames = [
  'Jan',
  'Feb',
  'Mar',
  'Apr',
  'May',
  'Jun',
  'Jul',
  'Aug',
  'Sep',
  'Oct',
  'Nov',
  'Dec'
]

/**
 * The Timeline is a widget for displaying and controlling the current scene time.
 * @alias Timeline
 * @constructor
 *
 * @param {Element} container The parent HTML container node for this widget.
 * @param {Clock} clock The clock to use.
 */
function Timeline(container, clock) {
  // >>includeStart('debug', pragmas.debug);
  if (!defined(container)) {
    throw new DeveloperError('container is required.')
  }
  if (!defined(clock)) {
    throw new DeveloperError('clock is required.')
  }
  // >>includeEnd('debug');

  container = getElement(container)

  const ownerDocument = container.ownerDocument

  /**
   * Gets the parent container.
   * @type {Element}
   */
  this.container = container

  const topDiv = ownerDocument.createElement('div')
  topDiv.className = 'cesium-timeline-main'
  container.appendChild(topDiv)
  this._topDiv = topDiv

  this._endJulian = undefined
  this._epochJulian = undefined
  this._lastXPos = undefined
  this._scrubElement = undefined
  this._startJulian = undefined
  this._timeBarSecondsSpan = undefined
  this._clock = clock
  this._scrubJulian = clock.currentTime
  this._mainTicSpan = -1
  this._mouseMode = timelineMouseMode.none
  this._touchMode = timelineTouchMode.none
  this._touchState = {
    centerX: 0,
    spanX: 0
  }
  this._mouseX = 0
  this._timelineDrag = 0
  this._timelineDragLocation = undefined
  this._lastHeight = undefined
  this._lastWidth = undefined

  this._topDiv.innerHTML =
    '<div class="cesium-timeline-bar"></div><div class="cesium-timeline-trackContainer">' +
    '<canvas class="cesium-timeline-tracks" width="10" height="1">' +
    '</canvas></div><div class="cesium-timeline-needle"></div><span class="cesium-timeline-ruler"></span>'
  this._timeBarEle = this._topDiv.childNodes[0]
  this._trackContainer = this._topDiv.childNodes[1]
  this._trackListEle = this._topDiv.childNodes[1].childNodes[0]
  this._needleEle = this._topDiv.childNodes[2]
  this._rulerEle = this._topDiv.childNodes[3]
  this._context = this._trackListEle.getContext('2d')

  this._trackList = []
  this._highlightRanges = []

  this.zoomTo(clock.startTime, clock.stopTime)

  this._onMouseDown = createMouseDownCallback(this)
  this._onMouseUp = createMouseUpCallback(this)
  this._onMouseMove = createMouseMoveCallback(this)
  this._onMouseWheel = createMouseWheelCallback(this)
  this._onTouchStart = createTouchStartCallback(this)
  this._onTouchMove = createTouchMoveCallback(this)
  this._onTouchEnd = createTouchEndCallback(this)

  const timeBarEle = this._timeBarEle
  ownerDocument.addEventListener('mouseup', this._onMouseUp, false)
  ownerDocument.addEventListener('mousemove', this._onMouseMove, false)
  timeBarEle.addEventListener('mousedown', this._onMouseDown, false)
  timeBarEle.addEventListener('DOMMouseScroll', this._onMouseWheel, false) // Mozilla mouse wheel
  timeBarEle.addEventListener('mousewheel', this._onMouseWheel, false)
  timeBarEle.addEventListener('touchstart', this._onTouchStart, false)
  timeBarEle.addEventListener('touchmove', this._onTouchMove, false)
  timeBarEle.addEventListener('touchend', this._onTouchEnd, false)
  timeBarEle.addEventListener('touchcancel', this._onTouchEnd, false)

  this._topDiv.oncontextmenu = function() {
    return false
  }

  clock.onTick.addEventListener(this.updateFromClock, this)
  this.updateFromClock()
}

/**
 * @private
 */
Timeline.prototype.addEventListener = function(type, listener, useCapture) {
  this._topDiv.addEventListener(type, listener, useCapture)
}

/**
 * @private
 */
Timeline.prototype.removeEventListener = function(type, listener, useCapture) {
  this._topDiv.removeEventListener(type, listener, useCapture)
}

/**
 * @returns {Boolean} true if the object has been destroyed, false otherwise.
 */
Timeline.prototype.isDestroyed = function() {
  return false
}

/**
 * Destroys the widget.  Should be called if permanently
 * removing the widget from layout.
 */
Timeline.prototype.destroy = function() {
  this._clock.onTick.removeEventListener(this.updateFromClock, this)

  const doc = this.container.ownerDocument
  doc.removeEventListener('mouseup', this._onMouseUp, false)
  doc.removeEventListener('mousemove', this._onMouseMove, false)

  const timeBarEle = this._timeBarEle
  timeBarEle.removeEventListener('mousedown', this._onMouseDown, false)
  timeBarEle.removeEventListener('DOMMouseScroll', this._onMouseWheel, false) // Mozilla mouse wheel
  timeBarEle.removeEventListener('mousewheel', this._onMouseWheel, false)
  timeBarEle.removeEventListener('touchstart', this._onTouchStart, false)
  timeBarEle.removeEventListener('touchmove', this._onTouchMove, false)
  timeBarEle.removeEventListener('touchend', this._onTouchEnd, false)
  timeBarEle.removeEventListener('touchcancel', this._onTouchEnd, false)
  this.container.removeChild(this._topDiv)
  destroyObject(this)
}

/**
 * @private
 */
Timeline.prototype.addHighlightRange = function(color, heightInPx, base) {
  const newHighlightRange = new TimelineHighlightRange(color, heightInPx, base)
  this._highlightRanges.push(newHighlightRange)
  this.resize()
  return newHighlightRange
}

/**
 * @private
 */
Timeline.prototype.addTrack = function(
  interval,
  heightInPx,
  color,
  backgroundColor
) {
  const newTrack = new TimelineTrack(
    interval,
    heightInPx,
    color,
    backgroundColor
  )
  this._trackList.push(newTrack)
  this._lastHeight = undefined
  this.resize()
  return newTrack
}

/**
 * Sets the view to the provided times.
 *
 * @param {JulianDate} startTime The start time.
 * @param {JulianDate} stopTime The stop time.
 */
Timeline.prototype.zoomTo = function(startTime, stopTime) {
  // >>includeStart('debug', pragmas.debug);
  if (!defined(startTime)) {
    throw new DeveloperError('startTime is required.')
  }
  if (!defined(stopTime)) {
    throw new DeveloperError('stopTime is required')
  }
  if (JulianDate.lessThanOrEquals(stopTime, startTime)) {
    throw new DeveloperError('Start time must come before end time.')
  }
  // >>includeEnd('debug');

  this._startJulian = startTime
  this._endJulian = stopTime
  this._timeBarSecondsSpan = JulianDate.secondsDifference(stopTime, startTime)

  // If clock is not unbounded, clamp timeline range to clock.
  if (this._clock && this._clock.clockRange !== ClockRange.UNBOUNDED) {
    const clockStart = this._clock.startTime
    const clockEnd = this._clock.stopTime
    const clockSpan = JulianDate.secondsDifference(clockEnd, clockStart)
    const startOffset = JulianDate.secondsDifference(
      clockStart,
      this._startJulian
    )
    const endOffset = JulianDate.secondsDifference(clockEnd, this._endJulian)

    if (this._timeBarSecondsSpan >= clockSpan) {
      // if new duration longer than clock range duration, clamp to full range.
      this._timeBarSecondsSpan = clockSpan
      this._startJulian = this._clock.startTime
      this._endJulian = this._clock.stopTime
    } else if (startOffset > 0) {
      // if timeline start is before clock start, shift right
      this._endJulian = JulianDate.addSeconds(
        this._endJulian,
        startOffset,
        new JulianDate()
      )
      this._startJulian = clockStart
      this._timeBarSecondsSpan = JulianDate.secondsDifference(
        this._endJulian,
        this._startJulian
      )
    } else if (endOffset < 0) {
      // if timeline end is after clock end, shift left
      this._startJulian = JulianDate.addSeconds(
        this._startJulian,
        endOffset,
        new JulianDate()
      )
      this._endJulian = clockEnd
      this._timeBarSecondsSpan = JulianDate.secondsDifference(
        this._endJulian,
        this._startJulian
      )
    }
  }

  this._makeTics()

  const evt = document.createEvent('Event')
  evt.initEvent('setzoom', true, true)
  evt.startJulian = this._startJulian
  evt.endJulian = this._endJulian
  evt.epochJulian = this._epochJulian
  evt.totalSpan = this._timeBarSecondsSpan
  evt.mainTicSpan = this._mainTicSpan
  this._topDiv.dispatchEvent(evt)
}

/**
 * @private
 */
Timeline.prototype.zoomFrom = function(amount) {
  let centerSec = JulianDate.secondsDifference(
    this._scrubJulian,
    this._startJulian
  )
  if (amount > 1 || centerSec < 0 || centerSec > this._timeBarSecondsSpan) {
    centerSec = this._timeBarSecondsSpan * 0.5
  } else {
    centerSec += centerSec - this._timeBarSecondsSpan * 0.5
  }
  const centerSecFlip = this._timeBarSecondsSpan - centerSec
  this.zoomTo(
    JulianDate.addSeconds(
      this._startJulian,
      centerSec - centerSec * amount,
      new JulianDate()
    ),
    JulianDate.addSeconds(
      this._endJulian,
      centerSecFlip * amount - centerSecFlip,
      new JulianDate()
    )
  )
}

function twoDigits(num) {
  return num < 10 ? `0${num.toString()}` : num.toString()
}

/**
 * @private
 */
Timeline.prototype.makeLabel = function(time) {
  const gregorian = JulianDate.toGregorianDate(time)
  const millisecond = gregorian.millisecond
  let millisecondString = ' UTC'
  if (millisecond > 0 && this._timeBarSecondsSpan < 3600) {
    millisecondString = Math.floor(millisecond).toString()
    while (millisecondString.length < 3) {
      millisecondString = `0${millisecondString}`
    }
    millisecondString = `.${millisecondString}`
  }

  return `${timelineMonthNames[gregorian.month - 1]} ${gregorian.day} ${
    gregorian.year
  } ${twoDigits(gregorian.hour)}:${twoDigits(gregorian.minute)}:${twoDigits(
    gregorian.second
  )}${millisecondString}`
}

/**
 * @private
 */
Timeline.prototype.smallestTicInPixels = 7.0

/**
 * @private
 */
Timeline.prototype._makeTics = function() {
  const timeBar = this._timeBarEle

  const seconds = JulianDate.secondsDifference(
    this._scrubJulian,
    this._startJulian
  )
  const xPos = Math.round(
    (seconds * this._topDiv.clientWidth) / this._timeBarSecondsSpan
  )
  const scrubX = xPos - 8
  let tic
  const widget = this

  this._needleEle.style.left = `${xPos.toString()}px`

  let tics = ''

  const minimumDuration = 0.01
  const maximumDuration = 31536000000.0 // ~1000 years
  const epsilon = 1e-10

  // If time step size is known, enter it here...
  let minSize = 0

  let duration = this._timeBarSecondsSpan
  if (duration < minimumDuration) {
    duration = minimumDuration
    this._timeBarSecondsSpan = minimumDuration
    this._endJulian = JulianDate.addSeconds(
      this._startJulian,
      minimumDuration,
      new JulianDate()
    )
  } else if (duration > maximumDuration) {
    duration = maximumDuration
    this._timeBarSecondsSpan = maximumDuration
    this._endJulian = JulianDate.addSeconds(
      this._startJulian,
      maximumDuration,
      new JulianDate()
    )
  }

  let timeBarWidth = this._timeBarEle.clientWidth
  if (timeBarWidth < 10) {
    timeBarWidth = 10
  }
  const startJulian = this._startJulian

  // epsilonTime: a small fraction of one pixel width of the timeline, measured in seconds.
  const epsilonTime = Math.min((duration / timeBarWidth) * 1e-5, 0.4)

  // epochJulian: a nearby time to be considered "zero seconds", should be a round-ish number by human standards.
  let epochJulian
  const gregorianDate = JulianDate.toGregorianDate(startJulian)
  if (duration > 315360000) {
    // 3650+ days visible, epoch is start of the first visible century.
    epochJulian = JulianDate.fromDate(
      new Date(Date.UTC(Math.floor(gregorianDate.year / 100) * 100, 0))
    )
  } else if (duration > 31536000) {
    // 365+ days visible, epoch is start of the first visible decade.
    epochJulian = JulianDate.fromDate(
      new Date(Date.UTC(Math.floor(gregorianDate.year / 10) * 10, 0))
    )
  } else if (duration > 86400) {
    // 1+ day(s) visible, epoch is start of the year.
    epochJulian = JulianDate.fromDate(
      new Date(Date.UTC(gregorianDate.year, 0))
    )
  } else {
    // Less than a day on timeline, epoch is midnight of the visible day.
    epochJulian = JulianDate.fromDate(
      new Date(
        Date.UTC(gregorianDate.year, gregorianDate.month, gregorianDate.day)
      )
    )
  }

  // startTime: Seconds offset of the left side of the timeline from epochJulian.
  const startTime = JulianDate.secondsDifference(
    this._startJulian,
    JulianDate.addSeconds(epochJulian, epsilonTime, new JulianDate())
  )
  // endTime: Seconds offset of the right side of the timeline from epochJulian.
  let endTime = startTime + duration
  this._epochJulian = epochJulian

  function getStartTic(ticScale) {
    return Math.floor(startTime / ticScale) * ticScale
  }

  function getNextTic(tic, ticScale) {
    return Math.ceil(tic / ticScale + 0.5) * ticScale
  }

  function getAlpha(time) {
    return (time - startTime) / duration
  }

  function remainder(x, y) {
    // return x % y;
    return x - y * Math.round(x / y)
  }

  // Width in pixels of a typical label, plus padding
  this._rulerEle.innerHTML = this.makeLabel(
    JulianDate.addSeconds(this._endJulian, -minimumDuration, new JulianDate())
  )
  let sampleWidth = this._rulerEle.offsetWidth + 20
  if (sampleWidth < 30) {
    // Workaround an apparent IE bug with measuring the width after going full-screen from inside an iframe.
    sampleWidth = 180
  }

  const origMinSize = minSize
  minSize -= epsilon

  const renderState = {
    startTime: startTime,
    startJulian: startJulian,
    epochJulian: epochJulian,
    duration: duration,
    timeBarWidth: timeBarWidth,
    getAlpha: getAlpha
  }
  this._highlightRanges.forEach(function(highlightRange) {
    tics += highlightRange.render(renderState)
  })

  // Calculate tic mark label spacing in the TimeBar.
  let mainTic = 0.0
  let subTic = 0.0
  let tinyTic = 0.0
  // Ideal labeled tic as percentage of zoom interval
  let idealTic = sampleWidth / timeBarWidth
  if (idealTic > 1.0) {
    // Clamp to width of window, for thin windows.
    idealTic = 1.0
  }
  // Ideal labeled tic size in seconds
  idealTic *= this._timeBarSecondsSpan
  let ticIndex = -1
  let smallestIndex = -1

  const ticScaleLen = timelineTicScales.length
  let i
  for (i = 0; i < ticScaleLen; ++i) {
    const sc = timelineTicScales[i]
    ++ticIndex
    mainTic = sc
    // Find acceptable main tic size not smaller than ideal size.
    if (sc > idealTic && sc > minSize) {
      break
    }
    if (
      smallestIndex < 0 &&
      timeBarWidth * (sc / this._timeBarSecondsSpan) >= this.smallestTicInPixels
    ) {
      smallestIndex = ticIndex
    }
  }
  if (ticIndex > 0) {
    while (ticIndex > 0) {
      // Compute sub-tic size that evenly divides main tic.
      --ticIndex
      if (Math.abs(remainder(mainTic, timelineTicScales[ticIndex])) < 0.00001) {
        if (timelineTicScales[ticIndex] >= minSize) {
          subTic = timelineTicScales[ticIndex]
        }
        break
      }
    }

    if (smallestIndex >= 0) {
      while (smallestIndex < ticIndex) {
        // Compute tiny tic size that evenly divides sub-tic.
        if (
          Math.abs(remainder(subTic, timelineTicScales[smallestIndex])) <
            0.00001 &&
          timelineTicScales[smallestIndex] >= minSize
        ) {
          tinyTic = timelineTicScales[smallestIndex]
          break
        }
        ++smallestIndex
      }
    }
  }

  minSize = origMinSize
  if (
    minSize > epsilon &&
    tinyTic < 0.00001 &&
    Math.abs(minSize - mainTic) > epsilon
  ) {
    tinyTic = minSize
    if (minSize <= mainTic + epsilon) {
      subTic = 0.0
    }
  }

  let lastTextLeft = -999999
  let textWidth
  if (timeBarWidth * (tinyTic / this._timeBarSecondsSpan) >= 3.0) {
    for (
      tic = getStartTic(tinyTic);
      tic <= endTime;
      tic = getNextTic(tic, tinyTic)
    ) {
      tics += `<span class="cesium-timeline-ticTiny" style="left: ${Math.round(
        timeBarWidth * getAlpha(tic)
      ).toString()}px;"></span>`
    }
  }
  if (timeBarWidth * (subTic / this._timeBarSecondsSpan) >= 3.0) {
    for (
      tic = getStartTic(subTic);
      tic <= endTime;
      tic = getNextTic(tic, subTic)
    ) {
      tics += `<span class="cesium-timeline-ticSub" style="left: ${Math.round(
        timeBarWidth * getAlpha(tic)
      ).toString()}px;"></span>`
    }
  }
  if (timeBarWidth * (mainTic / this._timeBarSecondsSpan) >= 2.0) {
    this._mainTicSpan = mainTic
    endTime += mainTic
    tic = getStartTic(mainTic)
    const leapSecond = JulianDate.computeTaiMinusUtc(epochJulian)
    while (tic <= endTime) {
      let ticTime = JulianDate.addSeconds(
        startJulian,
        tic - startTime,
        new JulianDate()
      )
      if (mainTic > 2.1) {
        const ticLeap = JulianDate.computeTaiMinusUtc(ticTime)
        if (Math.abs(ticLeap - leapSecond) > 0.1) {
          tic += ticLeap - leapSecond
          ticTime = JulianDate.addSeconds(
            startJulian,
            tic - startTime,
            new JulianDate()
          )
        }
      }
      const ticLeft = Math.round(timeBarWidth * getAlpha(tic))
      const ticLabel = this.makeLabel(ticTime)
      this._rulerEle.innerHTML = ticLabel
      textWidth = this._rulerEle.offsetWidth
      if (textWidth < 10) {
        // IE iframe fullscreen sampleWidth workaround, continued.
        textWidth = sampleWidth
      }
      const labelLeft = ticLeft - (textWidth / 2 - 1)
      if (labelLeft > lastTextLeft) {
        lastTextLeft = labelLeft + textWidth + 5
        tics +=
          `<span class="cesium-timeline-ticMain" style="left: ${ticLeft.toString()}px;"></span>` +
          `<span class="cesium-timeline-ticLabel" style="left: ${labelLeft.toString()}px;">${ticLabel}</span>`
      } else {
        tics += `<span class="cesium-timeline-ticSub" style="left: ${ticLeft.toString()}px;"></span>`
      }
      tic = getNextTic(tic, mainTic)
    }
  } else {
    this._mainTicSpan = -1
  }

  tics += `<span class="cesium-timeline-icon16" style="left:${scrubX}px;bottom:0;background-position: 0 0;"></span>`
  timeBar.innerHTML = tics
  this._scrubElement = timeBar.lastChild

  // Clear track canvas.
  this._context.clearRect(
    0,
    0,
    this._trackListEle.width,
    this._trackListEle.height
  )

  renderState.y = 0
  this._trackList.forEach(function(track) {
    track.render(widget._context, renderState)
    renderState.y += track.height
  })
}

/**
 * @private
 */
Timeline.prototype.updateFromClock = function() {
  this._scrubJulian = this._clock.currentTime
  const scrubElement = this._scrubElement
  if (defined(this._scrubElement)) {
    const seconds = JulianDate.secondsDifference(
      this._scrubJulian,
      this._startJulian
    )
    const xPos = Math.round(
      (seconds * this._topDiv.clientWidth) / this._timeBarSecondsSpan
    )

    if (this._lastXPos !== xPos) {
      this._lastXPos = xPos

      scrubElement.style.left = `${xPos - 8}px`
      this._needleEle.style.left = `${xPos}px`
    }
  }
  if (defined(this._timelineDragLocation)) {
    this._setTimeBarTime(
      this._timelineDragLocation,
      (this._timelineDragLocation * this._timeBarSecondsSpan) /
        this._topDiv.clientWidth
    )
    this.zoomTo(
      JulianDate.addSeconds(
        this._startJulian,
        this._timelineDrag,
        new JulianDate()
      ),
      JulianDate.addSeconds(
        this._endJulian,
        this._timelineDrag,
        new JulianDate()
      )
    )
  }
}

/**
 * @private
 */
Timeline.prototype._setTimeBarTime = function(xPos, seconds) {
  xPos = Math.round(xPos)
  this._scrubJulian = JulianDate.addSeconds(
    this._startJulian,
    seconds,
    new JulianDate()
  )
  if (this._scrubElement) {
    const scrubX = xPos - 8
    this._scrubElement.style.left = `${scrubX.toString()}px`
    this._needleEle.style.left = `${xPos.toString()}px`
  }

  const evt = document.createEvent('Event')
  evt.initEvent('settime', true, true)
  evt.clientX = xPos
  evt.timeSeconds = seconds
  evt.timeJulian = this._scrubJulian
  evt.clock = this._clock
  this._topDiv.dispatchEvent(evt)
}

function createMouseDownCallback(timeline) {
  return function(e) {
    if (timeline._mouseMode !== timelineMouseMode.touchOnly) {
      if (e.button === 0) {
        timeline._mouseMode = timelineMouseMode.scrub
        if (timeline._scrubElement) {
          timeline._scrubElement.style.backgroundPosition = '-16px 0'
        }
        timeline._onMouseMove(e)
      } else {
        timeline._mouseX = e.clientX
        if (e.button === 2) {
          timeline._mouseMode = timelineMouseMode.zoom
        } else {
          timeline._mouseMode = timelineMouseMode.slide
        }
      }
    }
    e.preventDefault()
  }
}

function createMouseUpCallback(timeline) {
  return function(e) {
    timeline._mouseMode = timelineMouseMode.none
    if (timeline._scrubElement) {
      timeline._scrubElement.style.backgroundPosition = '0 0'
    }
    timeline._timelineDrag = 0
    timeline._timelineDragLocation = undefined
  }
}

function createMouseMoveCallback(timeline) {
  return function(e) {
    let dx
    if (timeline._mouseMode === timelineMouseMode.scrub) {
      e.preventDefault()
      const x = e.clientX - timeline._topDiv.getBoundingClientRect().left

      if (x < 0) {
        timeline._timelineDragLocation = 0
        timeline._timelineDrag = -0.01 * timeline._timeBarSecondsSpan
      } else if (x > timeline._topDiv.clientWidth) {
        timeline._timelineDragLocation = timeline._topDiv.clientWidth
        timeline._timelineDrag = 0.01 * timeline._timeBarSecondsSpan
      } else {
        timeline._timelineDragLocation = undefined
        timeline._setTimeBarTime(
          x,
          (x * timeline._timeBarSecondsSpan) / timeline._topDiv.clientWidth
        )
      }
    } else if (timeline._mouseMode === timelineMouseMode.slide) {
      dx = timeline._mouseX - e.clientX
      timeline._mouseX = e.clientX
      if (dx !== 0) {
        const dsec =
          (dx * timeline._timeBarSecondsSpan) / timeline._topDiv.clientWidth
        timeline.zoomTo(
          JulianDate.addSeconds(timeline._startJulian, dsec, new JulianDate()),
          JulianDate.addSeconds(timeline._endJulian, dsec, new JulianDate())
        )
      }
    } else if (timeline._mouseMode === timelineMouseMode.zoom) {
      dx = timeline._mouseX - e.clientX
      timeline._mouseX = e.clientX
      if (dx !== 0) {
        timeline.zoomFrom(Math.pow(1.01, dx))
      }
    }
  }
}

function createMouseWheelCallback(timeline) {
  return function(e) {
    let dy = e.wheelDeltaY || e.wheelDelta || -e.detail
    timelineWheelDelta = Math.max(
      Math.min(Math.abs(dy), timelineWheelDelta),
      1
    )
    dy /= timelineWheelDelta
    timeline.zoomFrom(Math.pow(1.05, -dy))
  }
}

function createTouchStartCallback(timeline) {
  return function(e) {
    const len = e.touches.length
    let seconds, xPos
    const leftX = timeline._topDiv.getBoundingClientRect().left
    e.preventDefault()
    timeline._mouseMode = timelineMouseMode.touchOnly
    if (len === 1) {
      seconds = JulianDate.secondsDifference(
        timeline._scrubJulian,
        timeline._startJulian
      )
      xPos = Math.round(
        (seconds * timeline._topDiv.clientWidth) /
          timeline._timeBarSecondsSpan +
          leftX
      )
      if (Math.abs(e.touches[0].clientX - xPos) < 50) {
        timeline._touchMode = timelineTouchMode.scrub
        if (timeline._scrubElement) {
          timeline._scrubElement.style.backgroundPosition =
            len === 1 ? '-16px 0' : '0 0'
        }
      } else {
        timeline._touchMode = timelineTouchMode.singleTap
        timeline._touchState.centerX = e.touches[0].clientX - leftX
      }
    } else if (len === 2) {
      timeline._touchMode = timelineTouchMode.slideZoom
      timeline._touchState.centerX =
        (e.touches[0].clientX + e.touches[1].clientX) * 0.5 - leftX
      timeline._touchState.spanX = Math.abs(
        e.touches[0].clientX - e.touches[1].clientX
      )
    } else {
      timeline._touchMode = timelineTouchMode.ignore
    }
  }
}

function createTouchEndCallback(timeline) {
  return function(e) {
    const len = e.touches.length
    const leftX = timeline._topDiv.getBoundingClientRect().left
    if (timeline._touchMode === timelineTouchMode.singleTap) {
      timeline._touchMode = timelineTouchMode.scrub
      timeline._onTouchMove(e)
    } else if (timeline._touchMode === timelineTouchMode.scrub) {
      timeline._onTouchMove(e)
    }
    timeline._mouseMode = timelineMouseMode.touchOnly
    if (len !== 1) {
      timeline._touchMode =
        len > 0 ? timelineTouchMode.ignore : timelineTouchMode.none
    } else if (timeline._touchMode === timelineTouchMode.slideZoom) {
      timeline._touchState.centerX = e.touches[0].clientX - leftX
    }
    if (timeline._scrubElement) {
      timeline._scrubElement.style.backgroundPosition = '0 0'
    }
  }
}

function createTouchMoveCallback(timeline) {
  return function(e) {
    let dx
    let x
    let len
    let newCenter
    let newSpan
    let newStartTime
    let zoom = 1
    const leftX = timeline._topDiv.getBoundingClientRect().left
    if (timeline._touchMode === timelineTouchMode.singleTap) {
      timeline._touchMode = timelineTouchMode.slideZoom
    }
    timeline._mouseMode = timelineMouseMode.touchOnly
    if (timeline._touchMode === timelineTouchMode.scrub) {
      e.preventDefault()
      if (e.changedTouches.length === 1) {
        x = e.changedTouches[0].clientX - leftX
        if (x >= 0 && x <= timeline._topDiv.clientWidth) {
          timeline._setTimeBarTime(
            x,
            (x * timeline._timeBarSecondsSpan) / timeline._topDiv.clientWidth
          )
        }
      }
    } else if (timeline._touchMode === timelineTouchMode.slideZoom) {
      len = e.touches.length
      if (len === 2) {
        newCenter = (e.touches[0].clientX + e.touches[1].clientX) * 0.5 - leftX
        newSpan = Math.abs(e.touches[0].clientX - e.touches[1].clientX)
      } else if (len === 1) {
        newCenter = e.touches[0].clientX - leftX
        newSpan = 0
      }

      if (defined(newCenter)) {
        if (newSpan > 0 && timeline._touchState.spanX > 0) {
          // Zoom and slide
          zoom = timeline._touchState.spanX / newSpan
          newStartTime = JulianDate.addSeconds(
            timeline._startJulian,
            (timeline._touchState.centerX * timeline._timeBarSecondsSpan -
              newCenter * timeline._timeBarSecondsSpan * zoom) /
              timeline._topDiv.clientWidth,
            new JulianDate()
          )
        } else {
          // Slide to newCenter
          dx = timeline._touchState.centerX - newCenter
          newStartTime = JulianDate.addSeconds(
            timeline._startJulian,
            (dx * timeline._timeBarSecondsSpan) / timeline._topDiv.clientWidth,
            new JulianDate()
          )
        }

        timeline.zoomTo(
          newStartTime,
          JulianDate.addSeconds(
            newStartTime,
            timeline._timeBarSecondsSpan * zoom,
            new JulianDate()
          )
        )
        timeline._touchState.centerX = newCenter
        timeline._touchState.spanX = newSpan
      }
    }
  }
}

/**
 * Resizes the widget to match the container size.
 */
Timeline.prototype.resize = function() {
  const width = this.container.clientWidth
  const height = this.container.clientHeight

  if (width === this._lastWidth && height === this._lastHeight) {
    return
  }

  this._trackContainer.style.height = `${height}px`

  let trackListHeight = 1
  this._trackList.forEach(function(track) {
    trackListHeight += track.height
  })
  this._trackListEle.style.height = `${trackListHeight.toString()}px`
  this._trackListEle.width = this._trackListEle.clientWidth
  this._trackListEle.height = trackListHeight
  this._makeTics()

  this._lastXPos = undefined
  this._lastWidth = width
  this._lastHeight = height
}
export default Timeline
